FEEDING ELEMENT FOR FIBROUS MATERIAL

ELEMENT D'ALIMENTATION POUR MATIERE FIBREUSE

English Abstract

A feeding element intended for refiners with two
opposed refining means (11, 12), one of which is stationary and
one rotary, which are provided with refining elements (14, 15),
which between themselves form a refining gap (17) with a
refining zone (16) for working lignocellulosic fibrous material.
A feeding device (20, 22) is located centrally inside the
refining gap (17). The feeding element (30) is intended to be
placed on the rotary refining means (12) in the refining gap
(17} directly outside the feeding device (20, 22). The
feeding element (30) is formed with at least one feeding bar (31),
where the upper edge (33) of each feeding bar projects out on
at least one side of the bar.

French Abstract

L'invention concerne un élément d'alimentation destiné à des raffineurs possédant deux moyens de raffinage (11, 12) opposés, l'un étant stationnaire et l'autre rotatif. Ces moyens de raffinage possèdent des éléments de raffinage (14, 15) formant entre eux un espace de raffinage (17) avec une zone de raffinage (16) permettant le traitement de la matière fibreuse ligno-cellulosique. Un dispositif d'alimentation (20, 22) occupe une position centrale à l'intérieur de l'espace de raffinage (17). L'élément d'alimentation (30) est destiné à être placé sur le moyen de raffinage rotatif (12) à l'intérieur de l'espace (17) juste à l'extérieur du dispositif d'alimentation (20, 22). L'élément d'alimentation (30) est pourvu au moins d'une barre d'alimentation (31) dont le bord supérieur (33) fait saillie au moins d'un côté de celle-ci.

Claims

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CLAIMS:
1. A feeding element for use in connection with a
refiner for lignocellulosic fibrous material including a
stationary refining member, a rotary refining member mounted
for rotation in juxtaposition with said stationary refining
member thereby forming a refining gap therebetween, a feeder
for feeding said lignocellulosic fibrous material centrally
to a feed zone within said refining gap and a refining zone
extending radially outward from said feed zone, said feeding
element comprising a feeding member having an upper surface
for mounting on said rotary refining member at a location
outwardly displaced from and directly adjacent to said
central location of said feed zone, said feeding member
including at least one radial feed bar projecting from said
upper surface of said feeding member, said at least one
radial feed bar including a body portion and a projecting
portion extending laterally from said body portion at a
location displaced from said upper surface of said feeding
member.
2. The feeding element of claim 1 wherein said body
portion includes a first side and a second side, and said
projecting portion extends laterally from both said first
and second sides of said body portion.
3. The feeding element of claim 1 including a
plurality of said radial feed bars, and wherein said
projecting portions extending laterally from each of said
plurality of radial feed bars are spaced from adjacent ones
of said projecting portions.
4. The feeding element of claim 1 including a
plurality of said radial feed bars, and wherein said
projecting portions extending laterally from each of said
plurality of radial feed bars are connected to adjacent ones

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of said projecting portions to form bridges between said
plurality of radial feed bars, thereby creating closed
channels beneath said bridges.
5. The feeding element of claim 1 including a
plurality of said radial feed bars extending substantially
over said entire upper surface of said feeding member.
6. The feeding element of claim 1 wherein the outer
portion of said feeding element extending radially from said
feeding member includes a plurality of radially projecting
bars for working said lignocellulosic fibrous material.
7. The feeding element of claim 1 wherein said
feeding element comprises an annular feeding element
extending entirely around said rotary refining member.

Description

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Feeding element for fibrous material
This invention relates to a device for working lignocellulosic fibrous
material
in a refiner with opposed refining means rotating relative to each other, one
of which is stationary and one rotary, provided with refining elements, which
between themselves form a refining gap with a refining zone for working the
material. The material is supplied through a central opening in the stationary
refining means to a feed zone located radially inside the refining zone. The
invention, more precisely, relates to a feeding element for the material,
which
is intended to be placed directly outside a central feeding device on the
rotary
refining means. The feeding element according to the invention can be used
in a refiner for the manufacture of various types of mechanical pulps, such as
refiner mechanical pulp (RMP), thermomechanical pulp (TMP), chemi-
mechanical pulp (CMP) and chemi-thermomechanical pulp (CTMP). The
starting material can be wood chips or more or less worked pulp.
In the inner portion of the feed zone the effect of the centrifugal force on
the
supplied material is low. This implies, that the material supplied through the
opening in the stationary refining means is not fed sufficiently rapidly
through
the feed zone to the outside located refining zone. As a result therof, the
material can clog in the feed zone, which results in friction losses and non-
uniform feed, which in its turn deteriorates the pulp quality. In order to
over-
come these problems, mechanical feeding devices can be arranged in the feed
zone.
But even if the material by means of central feeding devices is transported
out
through the feed zone, problems can arise when it enters the refining zone in
the refining gap. The material can there be braked and subjected to an in-
effective mechanical action, which causes heat development and not the
desired working of the material. This results in unnecessarily high energy
consumption.

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The feeding element according to the present
invention offers a solution of the aforesaid problems, in
that it brings about a continued effective feed of the
material and at the same time its acceleration from the feed
zone and a distance into the refining gap. Due to the
effective feed, the energy consumption in the refiner is
reduced.
The refining element according to the invention
comprises at least one feeding bar where the upper edge of
each feeding bar projects out at least on one side of the
bar. The feeding element is intended to be placed on the
rotary refining means in the refining gap directly outside
the central feeding device, which can be attached on the
rotary refining means or be a separate screw feeder
extending in to the refining gap between the refining means.
The feeding bar or bars of the feeding element can be
angular in relation to the radius in order to bring about
optimum feeding. Alternatively, the feeding bar or bars can
be radial in order to allow reversing with maintained
feeding. In this case the upper edge of the feeding bar
projects out symmetrically on both sides of the bar.
The characterizing features of the invention are
apparent from the attached claims.
In accordance with the present invention, there is
provided a feeding element for use in connection with a
refiner for lignocellulosic fibrous material including a
stationary refining member, a rotary refining member mounted
for rotation in juxtaposition with said stationary refining
member thereby forming a refining gap therebetween, a feeder
for feeding said lignocellulosic fibrous material centrally
to a feed zone within said refining gap and a refining zone
extending radially outward from said feed zone, said feeding

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element comprising a feeding member having an upper surface
for mounting on said rotary refining member at a location
outwardly displaced from and directly adjacent to said
central location of said feed zone, said feeding member
including at least one radial feed bar projecting from said
upper surface of said feeding member, said at least one
radial feed bar including a body portion and a projecting
portion extending laterally from said body portion at a
location displaced from said upper surface of said feeding
member.
The invention is described in greater detail in
the following by way of embodiments thereof, with reference
to the accompanying drawings, in which
Fig. 1 is a cross-section through a refiner with a
feeding element according to the invention;
Fig. 2 shows a central feeding device;
Fig. 3 is a section according to III-III in
Fig. 2;

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Fig. 4 is a section according to IV-IV in Fig 2;
Fig. 5 shows an embodiment of a feeding element;
Fig. 6 is a section according to VI-VI in Fig. 5, and
Fig. 7 shows a variant of the embodiment shown in
Fig. 6.
The refiner shown in Fig. 1 comprises a refiner housing 10, in which a
stationary refining means 11 (in this case the end wall of the refiner
housing) and an opposed rotary refining means 12 attached on a rotary
shaft 13 are provided. The refining means 11,12 are provided with refining
elements 14 and, respectively, 15, which between themselves form a
refining zone I6 in a refining gap 17. The refining gap 17 comprises a feed
zone 18 located inside the gap. The stationary refining means 11 is formed
with a central feed opening I9 for the material to be worked. A screw
feeder 20 for the material is connected to the feed opening 19. The refiner
housing 10 is provided with an outlet 21 for the material passing through
the refining gap where it is worked.
On the rotary refining means a central feeding device 22 is located, which
comprises a circular disk 23 with strips 24 extending from a position close
to the centre radially outward to the circumference of the disk. The number
of strips can be one or more, preferably 2-4. The strips along the greater
portion of their upper edges are provided with a roof 25, which projects
out symmetrically on both sides of the strips.
The disk 23 is formed with a hub 26, from which three radial snips 24
extend. The roof 25 leaves an opening at the hub and follows the strips 24
outward. The height of the strips decreases outward in order to adapt to

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the outside located and outward tapering refining zone 16. The disk 23
has a diameter corresponding to the diameter of the feed opening 19.
The feeding device 22 is designed symmetrically in order to bring about
feed in both rotation directions. Alternatively, the feeding device can
be designed for rotation in only one direction.
It is also possible, that the central feeding device consists of a screw
feeder 20,
which then extends in through the feed opening 19.
A feeding element 30 is located on the rotary refining means 12 in the
refining gap 17 directly outside the feeding device 22. The feeding element
30 is formed with one or several radial feeding bars 31.
The feeding element can extend as a zone around the entire refining means i2
or consist of a portion of a zone and together with other feeding elements
extend around the refining means 12. According to Fig. 5, the number of
feeding elements is three, but also other numbers can be suitable. In order
to bring about an increased feeding effect, the feeding bars 31, instead, can
be angular in relation to the radius. This implies, however, that they operate
only in one rotation direction.
The feeding bars 31 of the feeding element 30 are formed with upper edges 33
projecting out symmetrically on both sides of the bars. The upper surface of
these upper edges 33 shall be flat, and the feeding bars 31 extend across the
refining gap 17 to the opposed stationary refining means 11, the correspond-
ing zone of which shall have smooth surface. The distance between the upper
edges 33 of the feeding bars and the opposed refining means 11 shall be short.
The feeding element 30 shall be so placed on the rotary refining means 12,
that a feeding bar 31 is located directly in front of a strip 24 on the
feeding
device 22.

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According to Fig. 6, the projecting upper edges 33 of adjacent feeding bars 31
are arranged spaced from each other, so that they bridge grooves 32 only
partially. According to the variant shown in Fig. 7, these upper edges,
instead,
are designed so as to totally bridge the grooves 32, so that closed radial
channels are formed.
Radially outside the feeding elements 30 both refining means 11,12 are
provided with refining elements for working the material. The refiner shown
has plane refining means, but it is also possible to give the outer portion of
the refining gap conical shape. Alternatively, the radially outer portion of
the feeding element 30 can be provided with conventional bars for working
the material in co-operation with bars on the opposed stationary refining
means 11. The number of conventional bars shall then be higher than the
number of feeding bars.
The material, which by the screw feeder 20 is fed into the refiner, is caught
under the roof 25 and accelerated outward along the strips. The material is
transferred from the feeding device 22 to the grooves 32 of the feeding
element 30 which effectively move the material into the refining zone 16
of the refining gap 17. Owing to the projecting upper edges 33 of the bars
31, the feed along the grooves 32 takes place with the effect of the
centrifugal force without being braked against the opposed stationary
refining means 11.
The material thereby is transferred effectively and uniformly to the
refining zone 16 without being disturbed by rearward flowing steam.
The working takes place longer away from the centre and thereby at a
higher relative speed between the refining means 11,12. On a whole,
this implies reduced specific energy consumption for working the material
to pulp.

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The alternative with an outer zone of conventional bars on the feeding
element 30 implies, that the transition from feeding to refining proceeds
softer, which can result in a more uniform material flow through the refiner.
The invention, of course, is not restricted to the embodiments shown, but
can be varied within the scope of the patent claims.

Representative Drawing